Greases are used in a wide variety of applications such as protecting and lubricating mechanical parts like ball and roller bearings and rotating shafts in vehicles, aircraft, machine tools and appliances, to mention but a few. Although greases consist of a lubricant base oil, a thickener and performance enhancing additives, the properties of the grease are due primarily to the properties of the lubricant base oil used in making the grease.
There are many applications for greases that possess simultaneously properties of low evaporation loss at high temperatures and adequate torque at low temperatures, such as lubricating aircraft ailerons, elevators, flaps and the like. However, this combination of properties is difficult to achieve, because lubricant base oils that provide adequate torque at low temperatures typically do not have low evaporation at high temperatures. The present invention is based on the discovery that greases meeting these seemingly incompatible properties can be formulated from Fischer-Tropsch wax derived base oils having high viscosity indicies (VIs).